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H. W. RUBINKAM.

AEROPLANE CONSTRUCTION.

APPLICATION FILED FEB. 14. 1919.

1 ,3 1 9, 1 1 7. Patented 001:. 21, 1919.

2 SHEETSSHEET I.

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H. W. RUBINKAM.

AEROPLANE CONSTRUCTION.

APPLICATION FILED FEB. 14. 1919.

1 ,3 1 9, 1 1 7. Patented 001;. 21, 1919.

2 SHEETS-SHEET 2.

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HENRY W. RUBINKAM, OF CHICAGO, ILLINOIS.

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To all whom it may concern Be it known that I, HENRY W. RUBINKAM, acitizen of the United States, residing at Chicago, in the county of Cookand State of Illinois, have invented certain .new and usefulImprovements in Aeroplane Constructions, of which the following is aspecification.

The present invention has to do with certain improvements in the stressmembers of aeroplanes and the like, particularly of the multiplane type,such as biplanes, etc. These stress members extend between the upper andlower wings or planes and join them together in such manner that theywill operate properly in unison. There are two sets of stresses to betaken care of in this connection, includingthe stresses of com,-pression and those of tension. The compression stresses are those whichtend to carry the planes closer together, and the tension stresses arethose which tendto separate the planes and move them farther apart.

In the past it has been customary to provide two sets of stress membersfortaking care of these two classes-of stresses. The stresses ofcompression were taken care of by compression struts which performpractically no other function than to maintain.

the planes separated the proper distance. The tension stresses weretaken care of by means of wire or cords extending between the two planesand which were entirely separate and distinct from the compressionstruts. Since the resistance to the movement of the machine through theair occasioned by the struts and wire is very large, it becomes verydesirable to reduce their number and size as much as possible. Thepresence of a large number of tension wires in addition to thecompression struts has been very disadvantageous and very objectionablefrom the standpoint of power necessary to drive the machine through theair as well as from the standpoint of interfering with its control inflight.

The main object of the present invention is to improve the form andconstruction of the stress member in such a manner that the stresses oftension and of compresslon-can.

both be taken care of'simultaneously, either directly or indirectly, andperforming both the tension and compression functions.

Another object of the lnvention 1s to 1mprove the form and constructlonof the stress Specification of Letters Patent. Application filedFebruary 14, 1919. Serial No. 277,014.

Patented Oct. 21, 1919.

members themselves and to improve the Another object of-the inventionhas to do with the manner in whichit is possible to balance the tensionproduced throughout the system so as to equalize the tension in thevarlous stress members, and so that the tension of the entire tensionsystem can be very readily and nicely adjusted.

Other objects and uses of the invention will appear from a detaileddescription of the same which consists in the. features of constructionand combinations of parts hereinafter described and claimed.

In the drawings:

Figure 1 shows a front view of the biplane having applied thereto thefeatures of the present invention Fig. 2 shows a longitudinal sectionthrough a stress member embodying the features of the present invention,and shows the manner in which thesame may be attached to. the upper andlower wings;

Fig. 3 shows a cross section line 33 of Fig. 2, looking in of the,arrows;

Fig. 4 shows a cross section taken on the line 44 of Fig. 2, looking inthe direction of the arrows; and

Figs. 5 and. 6 show in detailed form a simple type of expansion blockfor use. in

taken on the the direction securing the desired attachment on thetension members.

In thedrawings I haveillustrated a single application of the featuresofthe present invention to a bi-plane of simple form. It is to beunderstood, however, that in illustrating and describing this. singleembodiment of the features of invention, I do not in any way intend tolimit myself to the same except as I may do so in the claims.

Bearing the foregoing in mind, the machine illustrated includes theupper' wings 7 and 8 and the lower wings 9 and 10, the body 11,propeller 12, gear 13, and such other apparatus as is customary in theconstruction of machines of this kind.

Extending between each pair of upper and lower planes, are the stressmembers designated in their entirety by the numeral 14:. In theconstruction illustrated, the upper wings or planes are lon ger'than thelower ones, and there are provided three stress members between eachpair of planes, the

same extending in a zigzag fashion from a point on the lower wingadjacent to the body out to a point on the upper wing farthest removedtherefrom.

Compression struts have been used in the past for insuring properseparation between the planes, and it has been quite customary to makethe same hollow so as to lighten them without materially detracting fromtheir strength. It has, however, been held in the past to provideseparate tension members in the form of steel, cables or the like. Thesehave been strung between the planes quite separate and distinct from thepresence of the compression struts.

In carrying into efiect one of the features of the present invention, Iavail myself of the fact that the compression struts are sometimes madehollow so as to accommodate therein the tension cables or members. Theends of the latter are then joined to the upper and lower planes in suchmanner that they will effectively take up the tension forces. In thosecases in which it is customary to provide a number of distinctcompression struts, it is possible to pass the tension cablessuccessively through a number of them, so that a common length of cablecan be used for them all, in which case it is only necessary to providetwo points of anchor into the wings, thereby simplifying and improvingthe construction.

Referring again to the drawings, a simple form of the strut isillustrated in detail in Figs. 2 to 6 inclusive. It compresses a hollowshaft or bar generally of wood, its end portions 15 and 16 being broughtinto suitable engagement with the upper and lower wings 17 and 18respectively.

This strut let is generally of special cross section or contour, asshown in Figs. 3 and 4, so as to cause a minimum amount of windresistance when traveling in the direction of the arrows adjacent tosaid figures.

It has in the past been customary to provide a longitudinal here orpassage 19 through each of these compression struts for the purpose oflightening it. According to the present invention, I pass a tensioncable 20 through the strut and join or connect it to the wings or planesin suitable manner. For this purpose I provide metal tubular anchors 21and 22 in the end portion of the strut, which anchors extend over andconnect into the adjacent wings or planes. These tubular anchors servenot only to anchor the ends of the struts to the wings, but also beingtubular serve to pass the cable through the wings, so that they can bejoined or connected or anchored to them in the most convenient manner.

Vhere a number of stress members are used on each side of the machineas, for example, the arrangement shown in Fig. 1, the tension cable maybe passed in succession through the different members and have only itsend portions anchored. For example, the left side cable, in Fig. 1, mayhave its outer end anchored at the point 23 and its inner end anchoredat the point 24, and the right side cable, in said figure, may have itsouter end anchored at the point 25, and its inner end anchored at thepoint 26.

Where the cable passes from one stress member to another, it isconveniently passed clear through the framework or wings, as shown inFig. 2, and over a suitable abutment block. This abutment block, desinated in its entirety by the numeral 2?, serves not only to tie theframework to the stress members, but also serves to permit the tensioncable to equalize its tension by sliding or moving a slight amount ineither di rection, as the case may be. A convenient form of such blockis shown in detail in Figs. 5 and 6. It comprises the two sections 28and 29 which may be separated from each other a slight amount by meansof a tapered screw 30 so as to raise the section 28, and thus pull upthe cable so as to increase its tension. Lugs or beads 31 and 32 areprovided in the section 28 so as to guide the cable 20 over saidsection. The ends of the .cable are conveniently anchored in anysuitable manner as, for example, by the use of a loop 33 on the end ofthe cable in conjunction with a turnbuckle 34:, said turnbuckle havingits inner ends anchored to the frame of the machine.

I claim:

1. In an aeroplane of the plural wing type, the combination with theupper and lower wings, of a plurality of stress members extending inzigzag fashion between said wings, the end portions of consecutivestress members being in close proximity to each other, each stressmember being provided with a longitudinal passageway, tubular anchorsextending between the end portions of the stress members and theadjacent wings and serving to anchor the ends of the stress members tothe wings, a tension cable extending in succession through the severalstress members and over the wings, means for anchoring the end portionsof said ten sion cable to the wings, and expansion blocks locatedbetween the wings and the tension cable at the points where said cablepasses between successive stress members, substantially as described.

2. In an aeroplane of the plural wing type, the combination with .thewings thereof, of a plurality of stress members extending in zigzagfashion between the wings, the end portions of consecutive stressmembers being located relatively close together, the

wings being provided with longitudinal passageways, means for anchoringthe end portions of the stress members to the wings, a tension cablepassing in succession through the stress members and over the Wings, andmeans for anchoring the end portions of the tension cable to the Wings,substantially as described.

3. In an aeroplane of the plural Wing type, the combination With theWings thereof, of a plurality of stress members extending between theWings in zigzag fashion, said stress members being provided withlongitudinal passageways, means for anchoring the end portions of thestress members to the Wings, 4

and a tension cable extending through the Copies of this patent may beobtained for successive stress members over the Wings, substantially asdescribed.

4. In an aeroplane of the plural Wing type v 15 vextending in successionthrough the stress 20 members and over the Wings, substantially asdescribed.

HENRY WV. RUBINKAM.

Washington, D. 0."

